I have the following scenario. Two Grandstream phones GXP2160 registered with asterisk. Both phones have BLF configured on phone using the multi-Purpose keys (Lets say extension 300 and 301)

Both phones “monitor” each other using the BLF.
Both phones have call waiting enabled.

While 300 extension is busy, the BLF on 301 extension is solid red - correct
If 300 is ringing, the BLF on 301 extension is flashing red - correct
If 300 is currently talking and on the same time second call ringing(call waiting), the BLF on 301 extension is flashing red - correct but is there any change we can do to this??

So in the case that extension 300 is talking with a client and a second call comes in (ringing 300), extension 301 is not able to understand if 300 is busy or not, and so to call pickup.

Is there any other BLF option that in that case the BLF stays solid red or handles it any differently?